. The algae. Algae. Fig. 90 Petalonia fascia. A, plant ( x |). B, transverse section of thallus with plurilocular sporangia ( x 375). (A, original; B, after Setchell and Gardner.) because normally the gametophytic generation arises from the pro- ducts of unilocular sporangia. It would therefore seem premature to accept this pecuHar life cycle without further evidence, and at present it would be more in agreement with known life cycles if the plants are simply regarded as being wholly diploid and without a haploid generation. In the related genus Scytosiphon it would also seem that only the dip

This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.

This image could have imperfections as it’s either historical or reportage.

. The algae. Algae. Fig. 90 Petalonia fascia. A, plant ( x |). B, transverse section of thallus with plurilocular sporangia ( x 375). (A, original; B, after Setchell and Gardner.) because normally the gametophytic generation arises from the pro- ducts of unilocular sporangia. It would therefore seem premature to accept this pecuHar life cycle without further evidence, and at present it would be more in agreement with known life cycles if the plants are simply regarded as being wholly diploid and without a haploid generation. In the related genus Scytosiphon it would also seem that only the diploid generation is present and that the reported protonemata are not gametophytic as has been suggested by some workers. DiCTYOSiPHONACEAE: Dictyosiphon (dictyo, net; siphon, tube). Fig. 91 The filamentous plants arise from small lobed discs and have either a few or many branches, the younger ones commonly being clothed with deUcate hairs. In young plants there are the usual apical hairs with a basal meristem. Later the hairs are shed leaving 163. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press